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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<!--常量：程序执行过程中不能修改值。  -->
    <script>
        const pi = 3.14, userName = 'admin';
        console.log(pi);
        console.log(userName);
       // userName = '强哥';    //常量不能修改值
        console.log(userName);
        console.log(userName);
        console.log('---------数据类型--------');
        let istrue = true;
        console.log(istrue);
        istrue = false;
        console.log(istrue);
        console.log(typeof(istrue));    //输出变量的数据类型
        console.log('-------数值型--------');
        let num1 = 234, num2 =-3.45, num3 = 0x23;
        console.log(num1);  //
        console.log(num2);   //
        console.log(num3);
        console.log(typeof(num3));
        console.log('------字符型--------');
        let str1 = 'hello',str2 = '你好，强哥';
        console.log(str1);
        console.log(str2);
        console.log(typeof(str1));
        //在控制台输出以下内容：他说：“他想'强哥'给他当辅导员”；
        let  xs = "他说：\"他想强哥给他当辅导员\"" ;
        console.log(xs);
    </script>
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